The present invention relates to a coaxial cable connector, and more particularly, to a coaxial cable connector having a captive contact and being attached to the coxial cable using a direct crimp.
As is well known in the art, coaxial cables have an inner conductor surrounded by a dielectric which separates the inner conductor from a cylindrical conductor, typically a woven cable braid. The cable braid is in turn encased by an insulative cable jacket. Connectors are attached to coaxial cables to connect the cables to jacks or other connectors.
What is desired by many manufacturers using coaxial cables is a connector which has minimal machined parts and is therefore economical, yet at the same time provides a secure, captive pin contact. Connectors for coaxial cables in the prior art usually have one of these features but not all of them. For example, one of the simplest connectors is disclosed in U.S. Pat. No. 4,059,330. This patent teaches a connector consisting of four (4) elements--an inner pin contact or metallic prong attached to the inner conductor of the coaxial cable, a dielectric tubular plug which holds the pin contact and separates the braided outer conductor of the coaxial cable therefrom, an electrically conductive body and a threaded collar. The electrically conductive body is slipped over the jacket of the coaxial cable prior to assembly and the threaded collar is used to attach the coaxial cable to a jack or another connector and in doing so helps hold the components in place.
A more elaborate and secure connector is disclosed in U.S. Pat. No. 4,456,323. This patent teaches a variation of the "wedgelock" connector which has a captive inner pin contact and a good seal with the jacket of the coaxial cable, but requires a considerable amount of machining even in the simplified version disclosed in the '323 patent. As is known in the art, an inner pin contact can be rear-loaded into the body of a "wedgelock" connector prior to sealing by a wedge-nut which seals the rear of the connector when the wedge-nut is screwed into internal threads at the rear of the connector body.
A similar seal can be made when a clamping nut is used, as in U.S. Pat. No. 4,444,453. However, when a clamping nut is used, it is not possible to easily provide a captive inner pin contact since the body of the connector typically has a hole bored in it with a diameter just larger than the diameter of the dielectric of the coaxial cable. A clamping nut is then screwed onto the rear of the connector via external threads to seal the braided outer conductor and the jacket against the body of the connector.
A less expensive connector is a direct-crimp connector which uses a crimp tool to compress a crimp ring in place of the clamping nut used by the connector disclosed in the '453 patent. One prior art direct-crimp connector which includes a captive contact uses a Teflon insulator to hold a snap-in pin contact. However, when this type of connector is used with small coaxial cables, the inner conductor has a tendency to buckle when inserted into the pin contact.
Another type of connector that uses a crimp ring is a crimp-clamp connector in which the body is separated into two (2) parts so that the inner pin contact can be rear-loaded into the front end of the connector body. A clamp portion of the body is then attached to the connector body and a crimp ring is used to attach the coaxial cable to the clamp portion of the body. The result is a connector with a secure, captive inner pin contact, but which is relatively bulky due to the extra clamp portion. U.S. Pat. No. 4,280,749 (hereinafter the '749 patent) discloses a connector similar to the crimp-clamp connector. In the '749 patent the connector body passes over the cable jacket and locks into a resilient bushing around the cable jacket.
Direct-crimp coaxial cable connectors are disclosed in U.S. Pat. Nos. 4,400,050 and 4,239,313 (hereinafter the '050 and '313 patents) which are attached to coaxial cables by crimping the main body instead of a crimp ring. In the '050 patent, an inner tubular element is inserted between the cable dielectric and the cable braid of a coaxial cable and extends forward to provide an outer ring contact. The connector in the '313 patent is initially a one-piece unit including a main body which extends from an arrow-like part at the rear into a swivel nut portion at the front of the connector. The main body of the connector serves to retain the swivel nut and act as an outer ring contact. When the main body is crimped, the crimped portion breaks off the remainder of the connector, in other words, the '313 connector essentially includes a crimp ring which is merely temporarily attached to the main body.